Linear motor device and machine tool having the same mounted thereon

Abstract

The present invention provides a linear motor device that can reduce a variation in thrust caused by a variation in attractive force. The linear motor device includes a linear motor 1 and a control section 30 that controls the linear motor 1 . The linear motor 1 includes a magnet member 2 composed of permanent magnets having respective N poles and S poles alternately arranged in an axial direction, and a coil member 3 which is located orthogonally to the axial direction with respect to the magnet member 2 and through which the magnet member 2 is movable in the axial direction relative to the coil member 3 . The control section 30 controls current conducted through the coil member 3 so that a moving one of the magnet member 2 and the coil member 3 reciprocates within a use range L corresponding to a part of a pitch p between the magnetic poles N and S in the magnet member 2.

1. A linear motor device, comprising:
 a linear motor and a control section that controls the linear motor, the linear motor comprising a magnet member composed of permanent magnets having respective N poles and S poles alternately arranged in an axial direction, and 
 a coil member which is located orthogonally to said axial direction with respect to the magnet member and through which said magnet member is movable in the axial direction relative to the coil member, said control section controlling current conducted through said coil member so as to move said magnet member relative to said coil member by reciprocating said magnet member within a use range, 
 said use range corresponds to a range in an intermediate portion of a magnetic pole pitch where said magnetic pole pitch is a range between magnetic poles in each of the permanent magnets, wherein the attractive force in said range in said intermediate portion varies insignificantly relative to the attractive force in a vicinity of the magnetic poles of each of the permanent magnets which increases in variation 
 wherein the attractive force in said range in said intermediate portion varies insignificantly relative to the attractive force, which increases in variation in a vicinity of the magnetic poles of the magnetic member. 
 
     
     
       2. A machine tool having a linear motor device mounted thereon, comprising:
 processing means for processing a workpiece and a drive means for reciprocating the processing means, said machine tool being characterized in that said drive means comprises a linear motor and a control section that controls the linear motor, and said linear motor comprises a magnet member composed of permanent magnets having respective N poles and S poles alternately arranged in an axial direction, and 
 a coil member which is located orthogonally to said axial direction with respect to the magnet member and through which said magnet member is movable in the axial direction relative to the coil member, and in that said control section controls current conducted through said coil member so as to move said magnet member relative to said coil member, which is combined to said processing means, by reciprocating said magnet member within a use range, 
 said use range corresponds to a range in an intermediate portion of a magnetic pole pitch where said magnetic pole pitch is a range between magnetic poles in the magnet member, 
 wherein the attractive force in said range in said intermediate portion varies insignificantly relative to the attractive force, which increases in variation in a vicinity of the magnetic poles of the magnetic member. 
 
     
     
       3. A press machine having a linear motor device mounted thereon, comprising:
 a press processing means for executing processing so as to punch or form on a plate material and a drive means for driving the press processing means, said press machine being characterized in that said drive means comprises a linear motor and a control section that controls the linear motor, and said linear motor comprises a magnet member composed of permanent magnets having respective N poles and S poles alternately arranged in an axial direction, and 
 a coil member which is located orthogonally to said axial direction with respect to the magnet member and through which said magnet member is movable in the axial direction relative to the coil member, and in that said control section controls current conducted through said coil member so as to move said magnet member relative to said coil member, which is combined to said press processing means, by reciprocating said magnet member within a use range, 
 said use range corresponds to a range in an intermediate portion of a magnetic pole pitch where said magnetic pole pitch is a range between magnetic poles in the magnet member, 
 wherein the attractive force in said range in said intermediate portion varies insignificantly relative to the attractive force, which increases in variation in a vicinity of the magnetic poles of the magnetic member.